I have a question (am confused) about the the erase procedure. Does the erase strobe actually erase anything? It seems to me that the 'flash control sequence' following:

'on' 'hold erase' 'reset' 'on' 'release erase' 'reset' 'on'

... places the 30b in a 'receive' state, ready (as it were) to receive the MySamba send??

Is my understanding correct? comments??

---
also, if we don't actually send, is the firmware for the 30b still there?

One more, are the erase and reset pins TTL compatible ? I am thinking about making cross wired nand gates (flip flop) for contact debounce and hold... will the erase | reset work correctly if a standard TTL output from a nand gate strobes the positive signal on erase, or the ground shot on reset?

Do you folks think that the positive standard voltage of a TTL inverter will have enough current to power the calculator? ... power the flash?

They're CMOS compatible, with the max Vil and min Vih specs at 10% and 90% of the supply voltage, respectively. It will not necessarily work reliably driven by true TTL, but should work when driven by CMOS 74xx series parts (e.g., 74HC) on the correct supply voltage.

(01-28-2015 03:02 AM)MarkHaysHarris777 Wrote: I have a question (am confused) about the the erase procedure. Does the erase strobe actually erase anything? It seems to me that the 'flash control sequence' following:

'on' 'hold erase' 'reset' 'on' 'release erase' 'reset' 'on'

... places the 30b in a 'receive' state, ready (as it were) to receive the MySamba send??

Is my understanding correct? comments??

---
also, if we don't actually send, is the firmware for the 30b still there?

No, its ok really. Um, I did RTFM several times (and I'm still confused about it). The appendix is great for getting the job done (which is most important) but its not too great for understanding how some of the electronics work; which is important for designing an interfacing circuit.

I'm thinking of powering the calc from the three parallel TTL inverters 'locked' on. Then, the erase strobe can be the output of a flip flop that holds itself on; till reset of course. The FM doesn't speak to powering the unit with TTL, nor does it discuss TTL driving the erase strobe or reset... so just wondering. if my idea works I can also eliminate the LM117 volate regulator, and I can use some of the inverters (there are six) to drive the LEDs instead of discreet RTL components. (I'll let you know how it goes... if it doesn't work, I'll punt).

Never mind. :-} I finally understand whats happening. I have one of my calculators in that frustrating mode (following one erase cycle) where the machine appears dead. I have confirmed that the erase cycle, power-on, reset works; but no flash, yet, because MySamba can't negotiate with the stupid Prolific chip-set in my Dynex USB-Serial converter. Its a great null modem to me headless workstations, just can't use it to flash. rats. I'm still waiting on my FTDI converter to come by the mails. I get the infamous 'unable to connect' message; so I reset and unplugged everything.

I noticed something Jebem noted some days back, that even though the 'erased' machine appears dead its possible to check the voltage drop on the reset pin after a power-on. Even though the machine appears dead the voltage on J33 (reset) comes up to just less than Vcc (and stays there) until 'reset' is pressed; the voltage on pin J33 then drops to zero until the next power-on.

An inverter will power the unit, but I not think the forward + current has enough guts for the flash operation/ scrubbing that idea. I'll either go with a temp three volt power pack, or just wait until the LM117 gets here.

Lator gators... I'll be updating my PhotoJournal page later this morning when I get my pics processed.

(01-28-2015 06:02 AM)MarkHaysHarris777 Wrote: The appendix is great for getting the job done (which is most important) but its not too great for understanding how some of the electronics work; which is important for designing an interfacing circuit.

I'm thinking of powering the calc from the three parallel TTL inverters 'locked' on. Then, the erase strobe can be the output of a flip flop that holds itself on; till reset of course. The FM doesn't speak to powering the unit with TTL, nor does it discuss TTL driving the erase strobe or reset... so just wondering. if my idea works I can also eliminate the LM117 volate regulator, and I can use some of the inverters (there are six) to drive the LEDs instead of discreet RTL components.

So far, the manual is not written for an EE fiddling at the HW. Though not completely true due to App. H dealing with tuning your WP 34S, but you can do that without knowing about the signals at various points. Anybody who's trying to do more shall do his/her own measurements or ask the EEs on this forum who might be able to support him/her.

(01-28-2015 04:56 PM)walter b Wrote: So far, the manual is not written for an EE fiddling at the HW. Though not completely true due to App. H dealing with tuning your WP 34S, but you can do that without knowing about the signals at various points. Anybody who's trying to do more shall do his/her own measurements or ask the EEs on this forum who might be able to support him/her.

Totally, I get it. Actually, the only 'change' I might suggest for the manual is a clarification on 'when' the 30b loses its brains during the 'erase' power-on reset sequence. The manual is clear that upon exit the flashing will have replaced the 30b firmware. What needs to be clearer is that although you can run the (erase, power on, reset) sequence as many times as you want (and here is the rub) if your flash cable is talking to the 30b then your 30b firmware is GONE after the very first complete (erase, power-on, reset) regardless of whether the flash occurs. In other words, the sequence (erase, power-on, reset) destroys the 30b firmware... and if the flash does not work, the 30b is dead until a bonafide flash occurs. The instructions say this of course, but its not clear that before you press the button on MySamba the 30b firmware is GONE. If the flash does not work, you will not be playing with the 30b any longer 'till you get it figured out!

(01-29-2015 08:54 AM)MarkHaysHarris777 Wrote: ... the only 'change' I might suggest for the manual is a clarification on 'when' the 30b loses its brains during the 'erase' power-on reset sequence. The manual is clear that upon exit the flashing will have replaced the 30b firmware. What needs to be clearer is that although you can run the (erase, power on, reset) sequence as many times as you want (and here is the rub) if your flash cable is talking to the 30b then your 30b firmware is GONE after the very first complete (erase, power-on, reset) regardless of whether the flash occurs.

Hmmh, please let me quote the WP 34S manual, p. 253f:

"WARNING: Flashing your HP-20b or HP-30b will erase the firmware present on your calculator – your HP business calculator and its contents will then be gone. Its firmware will be replaced by the file you downloaded and its RAM will be cleared. Thereafter you will have a WP 34S RPN Scientific – i.e. your calculator will react as documented in this manual. This also means your calculator will not do anything useful for you after step 6 and before step 9 is successfully completed in the procedures described below."
(This text is printed in red there as well. Emphasis added.)

So, what do you want me to write more? And guess why that button is called "ERASE" by HP?

(01-29-2015 09:10 AM)walter b Wrote: This also means your calculator will not do anything useful for you after step 6 and before step 9 is successfully completed in the procedures described below.[/i][/color]"
(This text is printed in red there as well. Emphasis added.)

My interpretation (filters are great, aren't they?) reads that as 'your scientific calculator will not do anything useful ... after step six' meaning to me that the 34s will only be functional when the flash completes and the firmware is 'replaced'. But for some reason, in my brain, I thought that if the flash did not complete a reset on the machine (30b) would bring back the 30b. I thought HP called it 'erase' because its the strobe|switch that initiates the 'receive' of the firmware from the PC... thinking that if the firmware does not come down, the old firmware is still in memory and can be 'restored'. I think it is a dumb idea on HPs part to 'erase' the firmware (gone is gone) before we know if the comm link is going to work to restore it!

In the manual I would change that ONE bold red line to read something more specific (for those of us who are warning challenged) to say something along the lines of, "WARNING: The erase procedure wipes out the 30b firmware in preparation for the download of the 34s firmware. If the 'erase' works, but the firmware flash does not (comm link problem or other) the 30b will not boot-up into the business professional firmware and cannot be reset. DO NOT begin the process until you are prepared to LOSE the 30b firmware!"

I realize this i just a nit, and all other things considered it doesn't even matter... just saying.

I fully appreciate your description of the "frustrating state" in which your soon to be WP 34S is for all appearances, dead. As Walter states in his manual, despite that appearance in all likelihood the calculator is perfectly OK.

There are a few suggestions:

When you wrote you were using the 3V output present on the USB to serial converter I was very skeptical. In that regard I do not believe you will have any more (or less) success using the Prolific device vs. the FTDI. Its 3V output just doesn't have enough current.

For what it's worth a very similar project to yours using the Prolific device is detailed here, with great credit toward Jebem's design. From that, I took what I considered the most important design elements. It's 100% reliable.

From what I did, which involved many bonehead mistakes (not the least of which was confusing the pinouts of an LM1117 with the 7805 regulators I'm familiar with) I conclude it must be rather difficult to permanently kill the calculator. It's pretty resilient.

If you are concerned it's dead, measure the power supply current when it should be "on". If in doubt, press "on". That always turns it on. Conversely, Reset always turns it off. Power supply current in the "on" (but apparently dead) state will be approximately 8 mA. Press Reset and it will fall to zero.

I think your problems will be over if you use a real power supply instead of the 3V from the FTDI device. Even a single CR2032 battery is perfectly OK. If it gets weak though, you'll have flashing miseries. Weak cells may still measure 3V under no load, but if they're weak, they'll crash under load.

The LM1117 was a significant reason for building the box. The last thing I want to worry about is flaky power. Will the calculator erase properly with inadequate power? Who knows. I suspect that lies at the crux of your miseries.

(01-30-2015 03:43 AM)John Galt Wrote: The LM1117 was a significant reason for building the box. The last thing I want to worry about is flaky power. Will the calculator erase properly with inadequate power? Who knows. I suspect that lies at the crux of your miseries.

hi John, actually, I think you misunderstood me; I'm having no miseries... all is good, I have successfully flashed two units and they're working great. I just had an idea for making the manual a little clearer--- that's what Walter and I were discussing.

The FTDI adapter I'm using has plenty of power on the 3.3v line. That little device was specifically designed to work with the Arduino micro controller (hence the two voltages)... and will power it too! Any way, so far so good. I'm not sure how much current the actual flash procedure uses (let's measure it) anyway the 30b only consumes .25mw/ The voltage drop is 3.0 volts while the unit is being powered from the FTDI. I have flashed from batteries with a voltage reading of 2.6 volts.... so, the adapter is doing well.

After I have some time to measure the voltage/current during flash I'll get back to you.

(01-29-2015 06:14 PM)MarkHaysHarris777 Wrote: In the manual I would change that ONE bold red line to read something more specific (for those of us who are warning challenged) to say something along the lines of, "WARNING: The erase procedure wipes out the 30b firmware in preparation for the download of the 34s firmware. If the 'erase' works, but the firmware flash does not (comm link problem or other) the 30b will not boot-up into the business professional firmware and cannot be reset. DO NOT begin the process until you are prepared to LOSE the 30b firmware!"

I read that red paragraph in the manual again and it really starts with "WARNING" already. IMHO, that text as is tells exactly what you want it to tell. So, for the time being, I don't see a need to change it. Thanks for your understanding.

(01-28-2015 03:02 AM)MarkHaysHarris777 Wrote: I have a question (am confused) about the the erase procedure. Does the erase strobe actually erase anything?

Yes, ERASE is ERASE! With the original HP firmware running there is no way to clear the boot bit GPNVM1 which controls whether the flash memory or the built-in boot ROM takes control of the chip on power on. ERASE does two things: It clears the boot bit and erases the flash memory.

Once WP 34S firmware is loaded there is a second way to clear the boot bit: ON+D followed by ON+S+S. This leaves the flash memory intact and allows for the preservation of the backup RAM image stored in flash while updating the firmware.

Once the boot bit is cleared there is only one way to set it again to recover the flash contents: Use the original SAM-BA software by Atmel to set the bit. This only makes sense if there is a valid flash image left. After an ERASE this is definitely gone.

(01-28-2015 03:02 AM)MarkHaysHarris777 Wrote: I have a question (am confused) about the the erase procedure. Does the erase strobe actually erase anything?

Yes, ERASE is ERASE! With the original HP firmware running there is no way to clear the boot bit GPNVM1 which controls whether the flash memory or the built-in boot ROM takes control of the chip on power on. ERASE does two things: It clears the boot bit and erases the flash memory.

Once WP 34S firmware is loaded there is a second way to clear the boot bit: ON+D followed by ON+S+S. This leaves the flash memory intact and allows for the preservation of the backup RAM image stored in flash while updating the firmware.

Once the boot bit is cleared there is only one way to set it again to recover the flash contents: Use the original SAM-BA software by Atmel to set the bit. This only makes sense if there is a valid flash image left. After an ERASE this is definitely gone.

In any case you will lose the contents of RAM.

Thanks for the explanation, Marcus; and thanks for all you have done with this project-- very nice work.

I am nervous, because I know that every time I update my 34s, I first have to kill it! :-}

I plan to mod the unit with crystal and caps this week, and then another 'erase' flash cycle! Thanks again for everything/ The WP34s is quickly becoming my favorite calculator ever. Its faster than the 50g, its more fun than the 35s, and it leaves my TI units in the dust.

(02-01-2015 09:52 PM)Marcus von Cube Wrote: Once WP 34S firmware is loaded there is a second way to clear the boot bit: ON+D followed by ON+S+S. This leaves the flash memory intact and allows for the preservation of the backup RAM image stored in flash while updating the firmware.

I am nervous, because I know that every time I update my 34s, I first have to kill it! ...
I plan to mod the unit with crystal and caps this week, and then another 'erase' flash cycle! Thanks again for everything/ The WP34s is quickly becoming my favorite calculator ever. Its faster than the 50g, its more fun than the 35s, and it leaves my TI units in the dust.

Don't you be afraid. Flashing a WP 3xS for updates will happen frequently, thus your nervosity will decrease continuously following e^(-t/T_0). And thanks for your kind words.

(02-02-2015 03:14 PM)MarkHaysHarris777 Wrote: I am nervous, because I know that every time I update my 34s, I first have to kill it! :-}

When I first started using the WP-34S, I too felt nervous flashing it. But I have re-flashed my calculator dozens of times and it always works. Since you can still get HP-30B calculators from ebay for about $17.00, it might help relieve your nervousness to buy a couple spare units. I currently have three WP-34S calculators laying around so there is always one handy where ever I happen to be working. One in my computer room, one in my office, and one on my nightstand for those quick calculations that bug me before I go to sleep.

(02-02-2015 03:14 PM)MarkHaysHarris777 Wrote: I am nervous, because I know that every time I update my 34s, I first have to kill it! :-}

When I first started using the WP-34S, I too felt nervous flashing it. But I have re-flashed my calculator dozens of times and it always works. Since you can still get HP-30B calculators from ebay for about $17.00, it might help relieve your nervousness to buy a couple spare units. I currently have three WP-34S calculators laying around so there is always one handy where ever I happen to be working. One in my computer room, one in my office, and one on my nightstand for those quick calculations that bug me before I go to sleep.

hi hi, yup... already thinking in that direction; glad to see that someone else keeps their calculator(s) on the nightstand--- mine is there, along with my iPod (Mozart), my 2M transceiver (W0MHH), spare glasses, and a copy of the Bible (and a DIY LED reading light with a modified clip that fits my calculator; I'll post a photo later).

Just for fun I may try repurposing one of the 20b units for my collection. But I'd like to have one 34s with the last update, and one with the stable back-release.

(02-02-2015 03:14 PM)MarkHaysHarris777 Wrote: I am nervous, because I know that every time I update my 34s, I first have to kill it! :-}

You shouldn't ERASE a working 34S. Instead do the following:
... (see above)
The library will be replaced by what comes with the flash image but the RAM contents will be preserved.

Thanks Marcus! I did read about the hot key for storing ram to flash, but I have not tried it yet; very nice feature. This is one of the show stops for the 35s... no way to back it up! The 34s is much improved in *many* ways, but this ram to flash (save/restore) is one of the best!